The invention relates to deveining shrimp.
An automatic shrimp-deveining machine for handling high volumes of shrimp is described in U.S. Pat. No. 2,694,218, “Shrimp Deveining Machine,” F. S. Lapeyre et al., Nov. 16, 1954. That machine, shown in FIGS. 25 and 26, slits the back of a shrimp to expose and release the alimentary canal, or vein, to improve the appearance and delectability of the shrimp meat. The machine 20 has an inclined trough 22 supported in a frame 24 that allows manual adjustment of the inclination. A series of blade assemblies 26 are affixed to the trough 22. The blade assemblies 26 have knife blades 28 clamped between upper and lower clamp blocks 30, 31. The blade assemblies 26 are arranged angularly, or diagonally, with respect to the length of the trough 22 in a zig-zag pattern down the trough. Peeled shrimps are delivered to the upper end of the trough 22 by an infeed conveyor 32. The shrimps, lying on their sides, advance by gravity down the trough 22 in a zig-zag path P along the blade assemblies 26. Spray nozzles 34 direct water to lubricate the trough to help the shrimps advance, to wash the veins from the shrimps, and to clean the blade assemblies 26. Each shrimp slides down the water-lubricated trough 22 and successively encounters the blade assemblies. The blades 28 sever the membrane covering the vein. Multiple blade assemblies 26 are used to ensure that the membrane is severed along substantially the entire back of the shrimps. The water spray washes the exposed vein away. The deveined shrimps are carried away on a discharge conveyor 36 at the bottom end of the trough 22.
Commercial versions of the Lapeyre deveiner 20 work well, but have some shortcomings. For example, the height of the blades 28 above the trough 22 is fixed by the thickness of the lower blocks 31. To change blade heights, the lower blocks have to be changed. Replacing worn blades 28 is also a time-consuming task because the top clamp blocks 30 have to be removed to replace the blades. And changing the angles of the blade assemblies 26 also requires unbolting and re-bolting the assemblies one at a time. In operation the deveiner 20 has some shortcomings. For example, the blade assemblies 26 form barriers against which the water piles up. If too much water piles up, it can interfere with the shrimps' encounter with the blades 28.